Coupon for a carton



FIG. 1 is a front perspective view of a coupon for a carton showing my new design; and,

FIG. 2 is a rear perspective view thereof.

The broken line immediately adjacent the claimed coupon represents the bounds of the invention and forms no part of the claimed invention.

The dashed lines within the claimed coupon represent perforations. 

The ornamental design for a coupon for a carton, as shown and described. 